Duplicating or printing apparatus



June 23, 1931. R HARRls DUPLICATING OR PRINTING APPARATUS Filed Sept. 17. 1926 'inl Patented June 23, 19,31

ROBERT HARRIS, F LONDON, ENGLAND,

ASSIGNOR, RY MESNE ASSIGNMENTS, T0

LITHOPRINTEX CORPORATION, A CORPORATION OF DELAWARE' Y DUPLICATING OR PRINTING APPARATUS Appnaaon mea september 17, 192s, serial No. 136,017, and 1n Great Britain september 25,1925.

This invention is for improvements in or relating to duplicating or printing apparatus and particularly photographic step-and-repeat contact-printing machines. In such ma- `j chines arframe for holding a unit, for example a photographic negative, to be brought into intimate contact with apress plate of Zinc or aluminium, has been firmly secured face to face on a press member for pressing the lonnit on the press plate, but this arrangement did not provide for accommodating small differences in parallelism between thek press member and the support for the press plate, or small differences in thickness of the order of 25/1000ths of an inch between different parts of the unit, such differences in thickness constituting, for example, a taper towards one side or towards a corner of the unit. This invention has for its object to obviate this defect and to accommodate such differences in parallelism or thickness, so that pres sure shall be applied as uniformly as possible over as large an area of the unit as possible. i l

According to a primary feature of the in vention, there is provided in or for duplicat ing or printing apparatus, for example photographic step-and-repeat contact-printing apparatus, the combination with a press-member, and an unit-holdingframe, of resilient suspension means for mounting the frame on the press-member in substantially parallel relation whilst permitting one part of the frame (e. g. one corner thereof) to approach nearer to or recede further from the press member than another part thereof, for the purpose of automatically accommodating small inequalities in thickness either of the unit to be pressed, or the press plate against which the unit is to be pressed, and for accommodating small difference in parallelism between the pressing face of the press,

member and the support for the press plate.

According to another feature of the invention, the suspension means takes the form of a plurality of springs spaced apart around vt-he frame, each of which springs is so cont0 nected to the frame and to the press mem- .parts in all the views.

Vthe opposed face of the support.

ber as to constitute au universal joint connection. y

Preferably, the springs are in the form ofr leaf springs and are 'firmly connected each at itsY ends toone of said members'(forex ample-the frame) and at its central portion to thefotherof said members (for l example the press member) whereby there is provided an universal joint havinga limited range of action. o One illustrative embodiment of the inven-V tion is illustrated by way of example in the accompanying drawings, wherein- Figure 1 is a side elevation showing part of a press member and a press frame mounted thereon in accordance with the invention; Figure QE is a diagrammatic plan view of the press frame V'removed from'the 'apparatus, and f f l f 1 Figures 3 and 4 arerespectively aside ele vation, partly in"- vertical section, and top plan View of one corner of the press `member and `press frame with the means connectingr the same, but drawn toa scale larger than Figures 1 and 2.

Like reference characters y designate like i Referring to the drawings, a pressmember 10 movable towards and away from a fixed support 11 carries a rectangular press frame designated Vgenerally vby the numeral 12. This "frame serves in known manner to carry an unit, such as a photographic negative, not rvshown, intended to be pressed against plate, such as a sheet of zinc, or aluminium, also not shown, resting against the support 11. Itis very important that when the unit is a photographic negative it shall be pressed as uniformlyas possible over its entire area against the pressplate, and such'uniformity te of pressure is impaired if the thickness of either the' unit or thepress plate'is not the 1 same at one-edge as it isV at the opposite edge, or if the press member is not set parallel with In order "to accommodate such irregularities the press frame 12 is suspended at its four corners by springs 13 from the press y member 10. At each corner of theframe a leaf spring 13 is secured at its ends thereto v100 by bolts 14, Whilst the middle portion of eaeh leaf spring is bolted to the press member by a bolt 15 extending at right-angles to the lear` spring. Each of these resilient eonneetiens oi the frame l2 to the press member 10 constitutes a kind of universal joint that has a limited range of action and permits any one Corner of the frame to approach nearer to or recede further from the press member l0 and the support ll than the other corners Whilst preventing the frame from moving parallel to itself and laterally in relation to the press member 10. In this manner the small irregularities referred to above will be automatically aeeonnnodated, and the pressure will be. distributed uniformly over the entire area of the unit.

Various modiiications may be made in the details of eonstruction desribed above Without departing from the invention.

I claim l. ln'photographiestep-and-repeat contactprinting apparatus, the combination of alixed support,ravpress member movable towardsand away therefrom, leaf springs eaoh connected at the middle of its length to said press member, and anunit-holding frame connected to the said springs at their ends, siibstantially` as set forth.

v2. In duplicating apparatus, the combination of an apertured press member, a4 unit holdingframe registering therewith, and a plurality ot suspension means connecting said frame to said press member in substantially parallel. relation therto, which suspension means are resilient independently one ot ann other earh in a direction normaltothe press member to` permit not only slight bodily moyement ofV the. frame as` a Whole towards .and away irom the press member but also slight tilting `n aovement oi" theframe, but are substantially rigid in a direction at right an-v gles to that bodily movement to prevent the framefrom moving parallel to itself; and laterally in relationto the pressmember.

3. In. duplirating apparatus, the combination` oi: a, unit-holding open framethrough which lightA can pass, a. fixed support, aper-v tured press meansregistering with sai dfframe i'or advancing the latter towardsl said support, and a,l plurality of; means Connecting said 'l'rameand support and permitting attilting` movement of said irame'during `said advancing movement, Whilst preventinglateralA movement thereof parallel to itselfk and-lat erally inl relation to the. said press means.

4:. In photographie step-andfrellieat conf tact-printingl apparatus, the combination of; an apertured pressmember, a fixed support opposed thereto, an open unit-holding frame registering with the member, and a pluralityof springs connecting said frame to said pressmember at situations spaced apart in'suehmanner asto permit a` spring at one of said situations to flex to an extent difersireeo ing from that of the springs at the other situations, whereby the frame can tilt in relation to the press member.

In testimony whereof I ailix my signature.

ROBERT HARRIS. 

